Consider the following statements: 1. Diamond is hard and graphite is soft. 2. Diamond is soft and graphite is hard. 3. Diamond is a bad conductor, but graphite is a good conductor. 4. Diamond is a good conductor, but graphite is a bad conductor. Which of the statement(s) given above is/are correct?

Diamond and graphite are allotropes of carbon with distinct physical properties due to their bonding structures. Diamond is the hardest known natural substance because each carbon atom is bonded to four others in a rigid, three-dimensional tetrahedral structure [2]. In contrast, graphite is soft and slippery because its carbon atoms are arranged in hexagonal layers held together by weak van der Waals forces, allowing the layers to slide over each other [1]. Regarding electrical conductivity, diamond is an insulator (bad conductor) because all its valence electrons are localized in strong covalent bonds [1]. Graphite, however, is a good conductor of electricity because each carbon atom is bonded to only three others, leaving one delocalized electron per atom that is free to move through the layers [1]. Therefore, statements 1 and 3 are correct.

Sources

1. [1] Science , class X (NCERT 2025 ed.) > Chapter 4: Carbon and its Compounds > Allotropes of carbon > p. 61
2. [2] Science , class X (NCERT 2025 ed.) > Chapter 3: Metals and Non-metals > Table 3.1 > p. 40